It is standard practice in the United States and in other countries for broadcasters to insert into program material, at various times, a number of commercial messages of the program's sponsors. Many viewers find these messages to be an irritating interruption.
Accordingly, many techniques have been devised in an effort to avoid these commercial messages. One such technique is to mute the sound in response, for example, to the operation of a MUTE pushbutton on a remote control handunit. A remote control having such a mute function is known from the RCA CRK33 remote control transmitter handunit manufactured by Thomson Consumer Electronics, Inc., Indianapolis, Ind.
An improved sound muting technique is known from U.S. Pat. No. 3,870,956 (Wolff) issued 11 March 1975. Wolff discloses a circuit to mute the sound of a television receiver for a predetermined time, at the end of which time the receiver sound circuitry is automatically unmuted. The circuitry of Wolff, however, does not affect the video, and thus a viewer is subjected to a series of silent commercial messages.
Unfortunately, muting the sound does not remove the video of the unwanted commercial message. In addition, the viewer must watch the commercial in order to known when it has ended, and therefore, when the viewer can "unmute" the sound.
Of course, a viewer may simply select (i.e., "tune to") a second channel when a commercial message is displayed on a currently selected channel. A problem with this technique is that the viewer has no way of knowing when the commercial message on the originally selected channel has finished. Consequently, the viewer may be late in returning to the original channel, and may miss a portion of the program he was watching
A commercial message timer is known from co-pending U.S. patent application Ser. No. 261,243 (Johnson) filed 24 October 1988, entitled COMMERCIAL MESSAGE TIMER. In apparatus according to Johnson, a timer in a receiver is manually activated in response to the operation of a TIMER key, and may provide a countdown display on, for example, a television receiver display screen. If a channel change key is pressed while the timer is active, the current channel is stored and will be automatically retuned at the end of the timer period, unless a CLEAR key is pressed to cancel the function.
While the system of Johnson performs well, it requires two key activations each time a commercial is to be avoided (i.e., a TIMER key and a channel change key) and requires the activation of a CLEAR key to avoid automatic retuning of the original channel.